Since diphtheria antitoxin came into general use in 1894, serum therapy and prophylaxis for this and many other bacterial diseases have been employed widely. Following this type of treatment, serum reactions of greater or less severity have been frequent. In many clinics today the intradermal test for sensitivity to horse serum is employed before serum is administered. The test, however, has never been completely satisfactory because of the inconstancy of the relationship of serum reaction to sensitivity, as determined by this method. There is a definite need for a simple test which will give a more reliable index of the degree of susceptibility of an individual to serum.

In 1928, Spicer1 reported a series of 353 patients in whom the intradermal and ophthalmic tests for sensitivity to horse serum were contrasted. The results obtained by her suggested that the ophthalmic test is of considerably more value than the intradermal.